1. Field of the Invention
The invention pertains to the field of semiconductor processing equipment, and more particularly to a shadow framing system for use in semiconductor manufacturing over a large substrate or carrier.
2. Background Information
Large panel displays, such as those manufactured with thin film technology (hereinafter “TFT”), are used in a wide variety of electronic applications as a display device for presenting information to a user. Such displays, for instance active matrix liquid crystal displays (hereinafter “AMLCDs”) are often manufactured on a glass substrate (or over a carrier, which supports a substrate) of approximately 550 by 650 centimeters in dimension. In an exemplary environment, the displays comprise arrays of red, blue and green electronic cells that are driven through one or more grids of control lines.
The control lines are driven by control electronics elements, which are mounted to the substrate in one or more contact regions (metalization regions) on the upper surface of the substrate. The contact regions are generally free of semiconductor materials, such as SiN, a-Si, n+ Si, and Si films, these having been removed in semiconductor processing steps when the cell electronics were formed.
As the control electronics elements drive the control lines, the control lines in turn send signals to the cells. The signals electrically charge transistor lines in the cells, which cause a colored beam of light to be emitted. When several cells are combined, a spectrum of colors representing a discernable image will be created.
A shadow frame is occasionally employed in the semiconductor equipment that creates the large panel displays (that is, the equipment that deposits and etches semiconductor materials onto a substrate to create the TFT cells). In known systems, the shadow frame is a rectangularity shaped rim or lip that extends over the outer edges of a substrate and into the central deposition area approximately three to five millimeters. The shadow frame helps to hold the substrate in place and, in some cases, protects the substrate from warping and from deposition of material on the edges and backside of the substrate.
Some semiconductor equipment includes a shadow frame, while other equipment does not. For instance, the AKT, Inc., an of Applied Materials company, currently ships large panel display manufacturing units (e.g. the AKT 1600, 3500, 4300 and 5500 systems) that include a shadow frame, similar to what is described above, in the plasma enhanced chemical vapor deposition (hereinafter “PECVD”) process chamber.